This invention relates generally to light systems using light emitting diodes and more particularly concerns a pre-engineered, pretracked reeled L.E.D. system for lighting signs.
Some known L.E.D. lighting systems use long circuit boards with many L.E.D.""s distributed along the length of the board. The long circuit boards are generally not suitable for use in lighting housings which require curved or direction changing patterns of lights. If they are short enough to accommodate the space limitations resulting from changes in direction, they still must be separately mounted in channel clips before being secured in the housing. They also require calculation of the sizes of transformers, resistors and other circuit components necessary to handle each specific application. They must then also be wired in to the configuration of the system.
Other L.E.D. systems utilize metal tracks which can be bent to fit housings of various shapes, but the current boards must still be separately mounted in the track and then wired in the housing. These systems also require in-field mounting of the circuit boards on appropriate channel clips, fastening of the circuit boards in the housing and calculation of transformer sizes, resistors and other circuit components to accommodate the specific application. Boxes of circuit boards, channel clips, wiring and associated circuit elements complicate the task. The spacing of the boards and clips to achieve proper light distribution must be calculated and measured. Essentially, every application presents a unique design and assembly problem.
It is, therefore, an object of this invention to provide an L.E.D. system which is pre-engineered to provide a suitable light intensity per unit area. Another object of this invention is to provide an L.E.D. system which is pre-engineered to include all necessary circuit elements including properly sized transformers and resistors. A further object of this invention is to provide an L.E.D. system which is preassembled in a multi-directionally flexible array for rapid and easy installation in housings of any shape. Yet another object of this invention is to provide an L.E.D. system which is preassembled to include all necessary circuit board channel clips and attaching tape or the like. It is also an object of this invention to provide an L.E.D. system which uses the conductors electrically connecting the circuit boards as flexible structural connections between the circuit boards. Still another object of this invention is to provide an L.E.D. system which is connected in a flexible array for easy storage on and distribution from a reel.
In accordance with the invention, a lighting system includes a plurality of rigid circuit boards. Each of the circuit boards has a plurality of light emitting diodes dispersed on one of its faces. The diodes are electrically connected between the positive and negative terminals of their respective circuit board. The circuit boards are electrically connected in parallel with each other and structurally connected in series with each other by a plurality of pairs of flexible conductors connecting the positive and negative terminals of the circuit boards. The structural series connection results in a chain of circuit boards and conductors in a continuous circuit which is then spirally wound about the spool of a reel. The continuous circuit of boards is easily dispensed and aligned in the light housing. The system further includes a plurality of channel clips, one grasping each of the circuit boards, and a plurality of segments of double-backed adhesive, one adhered to each of the channel clips for easy mounting of the dispensed boards in the housing. Each of the clips may have a tab extending from an edge parallel to the direction of the chain to facilitate handling the chain during installation.
Each circuit board has at least one resistor electrically connected in series with its light emitting diodes sized to limit current through the diodes to a predetermined value. The light emitting diodes are preferably dispersed on their respective circuit boards in a geometric pattern predetermined to disperse light evenly over a predetermined geometric area. The geometric patterns are consistent from board to board and pre-engineered to provide a desired light intensity over the known geometric area. The circuit components are pre-calculated to limit the current in each circuit board.
The channel clips and adhesive are preassembled in the chain. The chain is flexible so as to follow the contour of the housing. Therefore, installation requires only dispensing the chain, pressing the adhesive of the clips to the housing and cutting the conductors at the last board to be used in the chain.
Most preferably, the light emitting diodes of each of the circuit boards are dispersed in the same geometric pattern with the diodes which are aligned in the direction of the length of the chain being dispersed at equal intervals. The pairs of conductors are of equal length, the length being predetermined to space all the diodes which are aligned in the direction of the length of the chain at equal intervals in a direction transverse to the length of the chain. Preferably, the light emitting diodes of each circuit board are also dispersed at equal intervals. The most preferred geometric pattern is a square. Such an arrangement permits the installer to use parallel chains, spacing all the transversely aligned diodes across the chains equally in housings having widths in multiples of the coverage of a single chain.